Biochemical investigations revealed persistent hypophosphatemia, elevated alkaline phosphatase, reduced tubular maximum reabsorption of phosphate per glomerular filtration rate (TmP/GFR), normal calcium and parathyroid hormone, and inappropriately normal 1,25(OH)2D. Radiographs showed pseudofractures, consistent with osteomalacia. This evidence concerns the gene PTH and osteomalacia.